WenDu=input("请输入带有符号的温度值")
if WenDu[-1]  in ['F','f']:
    C = (eval(WenDu[0:-1]) - 32) / 1.8
    print("转换后的温度是{:.2f}C".format(C))
elif WenDu[-1] in ['C','c']:
    F =1.8 * eval(WenDu[0:1])+32
    print("转换后的温度是{:.2f}F".format(F))
else:
    print("输入格式错误")
